OK, let's crack this. We're given 855 and our task is to multiply it by 135. Essentially, we'll be adding 855 to itself 135 times.
Step 1: 0 + 855 = 855
Step 2: 855 + 855 = 1710
Step 3: 1710 + 855 = 2565
Step 4: 2565 + 855 = 3420
Step 5: 3420 + 855 = 4275
Step 6: 4275 + 855 = 5130
Step 7: 5130 + 855 = 5985
Step 8: 5985 + 855 = 6840
Step 9: 6840 + 855 = 7695
Step 10: 7695 + 855 = 8550
Step 11: 8550 + 855 = 9405
Step 12: 9405 + 855 = 10260
Step 13: 10260 + 855 = 11115
Step 14: 11115 + 855 = 11970
Step 15: 11970 + 855 = 12825
Step 16: 12825 + 855 = 13680
Step 17: 13680 + 855 = 14535
Step 18: 14535 + 855 = 15390
Step 19: 15390 + 855 = 16245
Step 20: 16245 + 855 = 17100
Step 21: 17100 + 855 = 17955
Step 22: 17955 + 855 = 18810
Step 23: 18810 + 855 = 19665
Step 24: 19665 + 855 = 20520
Step 25: 20520 + 855 = 21375
Step 26: 21375 + 855 = 22230
Step 27: 22230 + 855 = 23085
Step 28: 23085 + 855 = 23940
Step 29: 23940 + 855 = 24795
Step 30: 24795 + 855 = 25650
Step 31: 25650 + 855 = 26505
Step 32: 26505 + 855 = 27360
Step 33: 27360 + 855 = 28215
Step 34: 28215 + 855 = 29070
Step 35: 29070 + 855 = 29925
Step 36: 29925 + 855 = 30780
Step 37: 30780 + 855 = 31635
Step 38: 31635 + 855 = 32490
Step 39: 32490 + 855 = 33345
Step 40: 33345 + 855 = 34200
Step 41: 34200 + 855 = 35055
Step 42: 35055 + 855 = 35910
Step 43: 35910 + 855 = 36765
Step 44: 36765 + 855 = 37620
Step 45: 37620 + 855 = 38475
Step 46: 38475 + 855 = 39330
Step 47: 39330 + 855 = 40185
Step 48: 40185 + 855 = 41040
Step 49: 41040 + 855 = 41895
Step 50: 41895 + 855 = 42750
Step 51: 42750 + 855 = 43605
Step 52: 43605 + 855 = 44460
Step 53: 44460 + 855 = 45315
Step 54: 45315 + 855 = 46170
Step 55: 46170 + 855 = 47025
Step 56: 47025 + 855 = 47880
Step 57: 47880 + 855 = 48735
Step 58: 48735 + 855 = 49590
Step 59: 49590 + 855 = 50445
Step 60: 50445 + 855 = 51300
Step 61: 51300 + 855 = 52155
Step 62: 52155 + 855 = 53010
Step 63: 53010 + 855 = 53865
Step 64: 53865 + 855 = 54720
Step 65: 54720 + 855 = 55575
Step 66: 55575 + 855 = 56430
Step 67: 56430 + 855 = 57285
Step 68: 57285 + 855 = 58140
Step 69: 58140 + 855 = 58995
Step 70: 58995 + 855 = 59850
Step 71: 59850 + 855 = 60705
Step 72: 60705 + 855 = 61560
Step 73: 61560 + 855 = 62415
Step 74: 62415 + 855 = 63270
Step 75: 63270 + 855 = 64125
Step 76: 64125 + 855 = 64980
Step 77: 64980 + 855 = 65835
Step 78: 65835 + 855 = 66690
Step 79: 66690 + 855 = 67545
Step 80: 67545 + 855 = 68400
Step 81: 68400 + 855 = 69255
Step 82: 69255 + 855 = 70110
Step 83: 70110 + 855 = 70965
Step 84: 70965 + 855 = 71820
Step 85: 71820 + 855 = 72675
Step 86: 72675 + 855 = 73530
Step 87: 73530 + 855 = 74385
Step 88: 74385 + 855 = 75240
Step 89: 75240 + 855 = 76095
Step 90: 76095 + 855 = 76950
Step 91: 76950 + 855 = 77805
Step 92: 77805 + 855 = 78660
Step 93: 78660 + 855 = 79515
Step 94: 79515 + 855 = 80370
Step 95: 80370 + 855 = 81225
Step 96: 81225 + 855 = 82080
Step 97: 82080 + 855 = 82935
Step 98: 82935 + 855 = 83790
Step 99: 83790 + 855 = 84645
Step 100: 84645 + 855 = 85500
Step 101: 85500 + 855 = 86355
Step 102: 86355 + 855 = 87210
Step 103: 87210 + 855 = 88065
Step 104: 88065 + 855 = 88920
Step 105: 88920 + 855 = 89775
Step 106: 89775 + 855 = 90630
Step 107: 90630 + 855 = 91485
Step 108: 91485 + 855 = 92340
Step 109: 92340 + 855 = 93195
Step 110: 93195 + 855 = 94050
Step 111: 94050 + 855 = 94905
Step 112: 94905 + 855 = 95760
Step 113: 95760 + 855 = 96615
Step 114: 96615 + 855 = 97470
Step 115: 97470 + 855 = 98325
Step 116: 98325 + 855 = 99180
Step 117: 99180 + 855 = 100035
Step 118: 100035 + 855 = 100890
Step 119: 100890 + 855 = 101745
Step 120: 101745 + 855 = 102600
Step 121: 102600 + 855 = 103455
Step 122: 103455 + 855 = 104310
Step 123: 104310 + 855 = 105165
Step 124: 105165 + 855 = 106020
Step 125: 106020 + 855 = 106875
Step 126: 106875 + 855 = 107730
Step 127: 107730 + 855 = 108585
Step 128: 108585 + 855 = 109440
Step 129: 109440 + 855 = 110295
Step 130: 110295 + 855 = 111150
Step 131: 111150 + 855 = 112005
Step 132: 112005 + 855 = 112860
Step 133: 112860 + 855 = 113715
Step 134: 113715 + 855 = 114570
Step 135: 114570 + 855 = 115425

So, 855*135 = 115425